1. Field
The described technology relates generally to an organic light emitting diode display.
2. Description of Related Art
An organic light emitting diode display includes two electrodes and an organic emission layer interposed therebetween, electrons injected from one electrode and holes injected from the other electrode are combined with each other in the organic emission layer to form an exciton, and light is emitted while the exciton discharges energy.
The organic light emitting diode display includes a plurality of pixels, each including an organic light emitting diode that is a self-light emitting element, and a plurality of thin film transistors and capacitors for driving the organic light emitting diode. The plurality of thin film transistors includes a switching thin film transistor and a driving thin film transistor.
In the switching thin film transistor, a thin gate insulating layer is formed between a gate electrode and a semiconductor layer to enable rapid switching operation. Because the thickness of the gate insulating layer of the driving thin film transistor, which is formed on the same layer as the switching thin film transistor, is reduced, a driving range of a gate voltage applied to the gate electrode of the driving thin film transistor becomes narrow. Therefore, it may be difficult to control the magnitude of the gate voltage Vgs of the driving thin film transistor to ensure a large number of gray levels.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology, and may therefore contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.